1. Field of the Invention
The present invention relates to vinyl aromatic resin compositions and more particularly flame retardant vinyl aromatic resin compositions.
2. Description of the Related Art
Brominated flame retardants and their use to flame retard vinyl aromatic resins such as acrylonitrile-butadiene-styrene (ABS) graft copolymers are generally known. More specifically, the use of brominated bisphenol A in ABS graft copolymer compositions is known. Such flame retarded compositions, however, typically suffer from one or more of the following deficiencies as the result of incorporating the flame retardant, namely, (a) poor ultraviolet light stability, (b) poor thermal color stability, (c) tendency to bloom, (d) low heat distortion temperature, (e) tendency to char, (f) low impact strength and/or poor melt flow (high viscosity). Additionally, various previously known compounds contained reactive groups which could undesirably lead to degradation of the thermoplastic resin.
Consequently, there is a need to provide a flame retardant vinyl aromatic resin composition overcoming one or more of the above deficiencies, and more particularly exhibiting in combination (a) no bloom, (b) good ultraviolet light stability, (c) thermal stability, (d) suitable levels of heat distortion temperature, impact strength and melt flow (sufficiently low viscosity), and (e) minimal degradation of the thermoplastic resin.